Low oil pressure?

It actually appears to be part of the restriction.... the flow area restriction at the rocker shaft to pedestal hole and it's bolt (approx .034 sq in) is about 30% smaller than the flow area in the cam holes (approx .049 sq in). It is the smallest flow area in that whole path from cam bearing to inside of the rocker shaft. So when the cam holes do align, then this shaft hole-to-bolt clearance comes into the equation.

(FWIW.... The PRW rockers set that I have has that shaft hole to bolt clearance area reduced to .012 sq in. I called them about it and they seemed to indicate that was for some flow control, though they were a tad vague on that point. It was more of a statement that there was enough oil coming through there.... CYA maybe....)